From the publication JP03060148 a laminated LCR element is known which provides a capacitance between two electrode layers in a sequence of layers stacked one on top of the other. To contact the electrode layers, they are conducted up to the edge of the sequence of layers, whereby outer contacts are arranged on the front surfaces of the component body.
From the publication JP2000226689A a component is known in which electrode layers located inside a multi-layered sequence are contacted, both by lateral outer electrodes and by solder balls arranged on the top side of the component.
An electrical component is indicated which provides a sequence of ceramic layers lying one on top of the other. Preferably electrode layers are provided between ceramic layers. The electrode layers can form at least one capacitor.
It is also advantageous if the ceramic layers lying one on top of the other form a base body, whereby contact surfaces are arranged on the outer surface of the base body.
In addition to at least one capacitor, it is advantageous if another electrical function is integrated in the form of a phase gate. The phase gate is thereby arranged on the top surface of the base body of its ceramic layer.
The electrode layers are further connected in an electrically conductive manner with the contact surfaces by means of the through contacts running inside the base body. The side surfaces of the base body are free of surface metallic contacts/free of metal plating.
The component indicated here makes use of the basic idea according to which capacitors are integrated into an electroceramic multi-layered component. For one thing, outwardly contacting the capacitors by means of through contacts largely eliminates parasitic influences that negatively affect the function or the properties of the component. In addition, the use of through contacts also provides an extremely space-efficient contact with the component.
By integrating at least one other phase gate in addition to the capacitor, especially advantageous filter elements can be realized, whereby the filter element with the capacitor and the phase gate has two electrical basic components that rotate the phase of an AC signal in opposite directions. This allows the creation of filters with good properties, for example high insertion loss and broadband filter characteristics. At the same time, the phase gate rotates the phase between voltage and power in a direction opposite to that of the capacitor. For example, the capacitor rotates the phase in the positive direction, while the phase gate rotates the phase in the negative direction.
By arranging the phase gate on a ceramic layer, the phase gate can be integrated into the component in such a way that little space is used. Connecting the capacitor with contact surfaces on an outer surface of the base body makes it easy and convenient to contact the component, for example on a printed circuit board.
In one advantageous embodiment of the component, the phase gate can be represented by a resistor or by an inductance. An especially advantageous option is to design the phase gate as a layer resistor. A layer resistor of this type can be integrated in an especially space-efficient manner by arranging it on a ceramic layer in the component.
In one especially advantageous embodiment of the component, all ceramic layers are made of the same material. This allows the component to be made especially light by jointly sintering ceramic green film. In this case, any shrinkage that occurs cannot be adjusted.
Another embodiment of the component provides that all ceramic layers contain an electrical functional ceramic. The term “electrical functional ceramics” means materials that, for example, provide a high dielectric constant when capacitors are realized or, for example, provide a suitable voltage dependency for their resistors when varistors are realized. In terms of the component described here, functional ceramics above all have the property that they provide at least one electrical function in addition to the mechanical support function that gives the component its mechanical stability and which also supports electrode layers or other electrically conductive elements. The voltage dependency of the electrical resistor or the dielectricity constant was already indicated.
However, other material properties that can make an electrical functional ceramic from a conventional ceramic material used as a support are also possible. Specifically, a temperature dependency of the electrical resistor, a temperature dependency of the dielectricity constant or other similar properties are possible. Especially interesting for this invention are materials that are needed for realizing capacitors, varistors or inductances.
Also advantageous is a component in which the electrode layers and phase gates are contacted exclusively by means of the contact surfaces. The contact surfaces are located on an outer side of the base body, preferably on the top or bottom side of the base body, whereby the contact surfaces are contacted by means of through contacts. This embodiment of the component has the advantage that an especially space-efficient contact can be achieved. This embodiment also has the advantage that outer contacts to be arranged on the sides of the base body can be eliminated. This reduces the overall surface needed for the contacts, which can drastically reduce the component's susceptibility to failure as well as drastically reduce parasitic capacities and inductances.
In another embodiment of the component, the electrode layers and the phase gates are arranged at various planes. The electrode layers and the phase gates are advantageously arranged on top of one another. This has the advantage that only a relatively small footprint is used to create the component. Such components can be advantageously used especially in applications where space is a critical factor.
In one especially advantageous embodiment, the component can be designed so that the basic space requirement for the base body is only limited by the necessary capacity or by the required electrical resistor or the required inductance. The number of capacitors also limits the footprint required to integrate several capacitors that are located next to one another in the component.
A through contact generally has the property that it electrically connects the top side of a ceramic layer with its bottom side in an electrically conductive manner and to that end passes through the ceramic layer in the “thick” direction. For example, providing the ceramic layer with a hole that is filled with a conductive paste can create a through contact. The through contact can also be manipulated in the process of common integration during the sintering of the sequence of ceramic layers.
In another embodiment of the component, the capacitors and the phase gates form a filter switch. It is especially advantageous if the elements that are part of the filter are connected inside the base body. For example, the use of through contacts can be especially helpful in this instance.
In another embodiment of the component, a common contact surface is arranged in the middle of the outer surface; the contact surface is connected to one or more electrode layers. The common contact surface is preferably reconnected to the electrode layer or layers by a through contact. The electrode layers connected to the common contact surface form common electrodes for several capacitors. This means that the common electrodes can form the counter electrodes for various capacitors.
Another embodiment of the component provides a symmetrical design in which the component is formed symmetrically at a level that runs through the common contact surface. In this example, the common outer contact surface forms a point of symmetry, and the component can be symmetrically created around this point of symmetry. This design has the advantage of being very easy to manufacture.
In one particularly advantageous embodiment of the component, a phase gate is executed as a layer resistor or as a layer inductance. All phase gates can also be executed as layer resistors. It is also possible to execute one phase gate as a layer resistor and another phase gate as layer inductances.
The inductance can be present as a conductive path that is curved in several places, for example in the form of a meander or a spiral.
In another embodiment of the component, multiple filters are integrated. This embodiment has the advantage that the space-saving effect is increased. This can be realized, for example, by having several capacitors use the common electrodes.
In another embodiment of the component, a broadband filter is formed for electromagnetic interferences. Such a filter can, for example, filter frequency ranges between 800 MHz and 2500 MHz. However, using the component described here, it is also possible to create filters against electromagnetic interferences (RFI filters); these filters filter down into the kHz range.
In another embodiment of the component, one or more varistors can be contained. Varistors have the advantage that they facilitate the creation of ESD (Electro-Static Discharge) filters. Varistors are characterized in that they have a voltage dependent resistor. In the context of the component described here, they can, for example, be realized by arranging a ceramic layer containing a varistor material between two electrode layers. From the two electrode layers is created a component that represents a parallel circuit consisting of one varistor and one capacitor.
Another embodiment of the component provides that a common electrode layer overlaps four different areas of other electrode layers. With the help of one such embodiment, four different capacitors can be integrated into one component of the type described here, which is particularly space-efficient.
In another embodiment of the component, several identical filters can be integrated.
In another embodiment of the component, several different filters can be integrated.
In this connection, “identical filters” means those filters where the circuitry of the electrical components is identical and where the electrical components essentially exhibit the same characteristics.
In another embodiment of the component, a layer resistor can be arranged between two ceramic layers. With regard to this embodiment, it should be noted that the material for the layer resistor preferably should be a material that can be co-fired with the ceramic layers involved. In terms of varistor ceramics, in this instance it is especially advantageous to use for the layer resistor a metalliferous paste that is also used for the electrode layers. To obtain relatively high resistance values, it is therefore advantageous to execute the layer resistor in the form of a path curved in several places. With the help of this type of path that is curved in several places, resistances between 0.1 and 50 Ω can be realized. Such a component can be a particular advantage when used in circumstances where negligible dissipation loss and therefore negligible resistances are desired.
In another embodiment of the component, the layer resistor is arranged on an outer side of a ceramic layer. In this case, there is a greater range of possibilities in the selection of the layer-resistor materials because when the layer resistor is attached to an outer side of a ceramic layer, co-firing is no longer absolutely required. In addition and especially in this case, the use of the materials typically used for high resistances, for example RuO2, can significantly reduce the existing risk of damage to the ceramic. Such a risk is especially pronounced for varistor ceramics. In this case, one would first debind and then sinter the sequence of ceramic layers lying one on top of the other. The layer resistor is only applied as the last temperature step is being carried out. Because of the moderate temperatures employed during the last temperature step, it is no longer possible for the layer-resistor material to damage the ceramic layers. With the help of such a layer resistor applied on an outer side of a ceramic layer or on an outer side of the base body, resistance values between 0.05 and 100 Ω or even more can be realized. This embodiment is especially advantageous for filter applications requiring an impedance adjustment. Protective layers of insulation applied later can cover the layer resistor arranged on the surface.
Another embodiment of the component provides that the footprint of the base body be smaller than 2.5 mm2. The footprint is thus the top or bottom side of the base body, which lies parallel to the ceramic layers, one of which supports the contact surfaces. In this case, at least four capacitors and two phase gates are integrated.
In another embodiment of the component, the footprint of the base body measures less than 5.12 mm2. In this case, at least eight capacitors and at least four phase gates are integrated.
In another embodiment of the component, the footprint of the base body measures less than 8 mm2. In this case, eight, ten, twelve or even more capacitors are integrated. At least four phase gates are also integrated.
In another embodiment of the component, all capacitors integrated into the base body have the same capacity. In addition, all integrated phase gates exhibit the same electrical characteristics. For example, all integrated resistors would exhibit the same resistance. All integrated inductances would exhibit the same inductance.
In another embodiment of the component, at least two capacitors that exhibit different capacities are integrated. In addition, at least two phase gates that exhibit different characteristics are integrated. For example, two resistors that exhibit different resistances are integrated. Furthermore, two inductances that exhibit different inductances can also be integrated.
Another embodiment of the component provides a capacitor material as the material for the ceramic layers. Possible capacitor materials specifically include: COG, X7R, Z5U, Y5V or HQM materials. Involved here are single or multi-phase oxide systems with specific characteristics. The use of capacitor materials is especially possible if an EMI broadband filter is supposed to be realized.
Another embodiment of the component provides a varistor ceramic as the material for the ceramic layers. In this case, specifically an ESD filter can be realized. Possible material systems specifically include: ZnO—Bi and ZnO—Pr.
Another embodiment of the component provides a material as the material for the electrode layers, which material contains one or more materials from the following list of materials: silver, palladium, platinum, silver-palladium alloys, silver-platinum alloys, copper, nickel.
These materials have the advantage that they exhibit good electrical conductivity. In addition, they can be sintered together with an appropriate paste and combined with the ceramic layers preferably used here.
Another embodiment of the component provides a material as the material for layer resistors, which material contains one or more elements from the following list of materials: silver, palladium, platinum, silver-palladium, silver-platinum, silver-palladium-platinum.
These materials have the advantage that they can be sintered together with the materials preferably used here for the ceramic layers, and that when they are sintered together they do not damage the varistor ceramics described here. Another embodiment of the component provides a material as the material for the layer resistor, especially for a layer resistor located on the top surface of the base body, which material contains one or more elements from the following list of materials: RuO2, Bi2Ru2O7, C, Ti2N, LaB6, WO2, Al2O3, and various PbO compounds.
In another embodiment of the component, the components integrated into the component form an RC filter, an T filter or a Π filter.
In another embodiment of the component, the components integrated into the component from an ESD filter.
In another embodiment of the component, all ceramic layers are made from a uniform ceramic material.
Also indicated is a switching mechanism with the component, whereby the component is executed so that it contains two filters, and whereby the component connects an amplifier and a speaker.
The component and a switching mechanism is explained in greater detail below using exemplary embodiments and related figures.